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Histopathologic evaluation of liver biopsy specimens yields information that is not otherwise obtainable and is frequently essential for diagnosing hepatic disease. Percutaneous needle biopsy, laparoscopic biopsy, and surgical biopsy each have their own set of advantages and disadvantages. Care should be taken to ensure an adequate amount of tissue is collected for meaningful histologic evaluation. Because sampling error is a limitation of hepatic biopsy, multiple liver lobes should be biopsied. This article discusses the indications for liver biopsy, associated risks, advantages and disadvantages of different biopsy techniques, and strategies to get the most useful information possible out of this process.

Hepatic Hodgkin lymphoma is a rare disease, characterized by the presence of abundant granulofibrous stroma, and its radiological features have rarely been described. We report a 67-year-old man, who presented with liver masses that showed apparent delayed enhancement, along with systemic lymphadenopathy and musculoskeletal lesions. Repeated percutaneous needle biopsy, however, failed to confirm the diagnosis, and surgical biopsy finally revealed small amount of Hodgkin cells and Reed-Sternberg cells. In this report, the radiological features of hepatic Hodgkin lymphoma will be presented and discussed, in correlation with its histological findings.

Highlights • IHPT is difficult to distinguish from malignant tumors • Knowledge of IHPT is necessary to allow for treatment, even without experience., Introduction Inflammatory hepatic pseudotumor (IHPT) is an important benign liver disease because it is difficult to clinically and radiologically distinguish from malignant tumors. Presentation of case Here, we describe a case of a 67-year-old male patient diagnosed with multiple inflammatory hepatic pseudotumors. The patient had undergone left hemicolectomy for descending colonic cancer (T3 N0 M0 stage IIA) 2 years prior. He underwent segment 6 and segment 7 partial hepatectomy because of suspected liver metastasis. The patient had an unremarkable postoperative course and was discharged 7 days after surgery. Marked infiltration of inflammatory cells was observed on histological examination. The patient was finally diagnosed with IHPT of the fibrohistiocytic type. Discussion Repeated imaging studies over 1 month showed the spontaneous regression of the hepatic tumors. Therefore, knowledge regarding this condition is necessary to allow for treatment, even in the absence of experience. During examination, it may be important to ascertain lesion size. Moreover, percutaneous needle biopsy and follow-up examinations are necessary for cases of suspected IHPT. Conclusion Hepatectomy should be considered if the lesion is suspected to be an IHPT.

Angiosarcoma arising in the retroperitoneal space is rare. We report a case of perirenal angiosarcoma presenting preoperative diagnostic difficulties. A 49-year-old man was referred to our department with left kidney mass. Specimens of CT-guided percutaneous needle biopsy of the mass did not contain any atypical cells suggestive of malignancy. A CT scan 6 months after embolization of the tumor revealed growth of the mass and two space-occupying lesions appearing in the liver. Laparoscopic resection of the left kidney with perirenal mass and one of the liver lesions was performed. Histopathological findings confirmed a diagnosis of perirenal angiosarcoma with hepatic metastases.

Percutaneous needle biopsy is almost exclusively performed under imaging guidance, using either ultrasound or computed tomography. Although accepted as a relatively safe procedure, percutaneous needle biopsy is certainly not risk-free. One of the potential serious complications after a percutaneous biopsy is tumor seeding which is relatively poorly understood and documented. Neoplasm seeding is defined as a local implantation of tumor cells by contamination of instruments and surgical equipment resulting in local growth of the cells and tumor formation (according to the National Library of Medicine of the National Institutes of Health, USA). Frequency and mechanisms behind tumor seeding after biopsy are poorly elucidated. In the four largest surveys the range of the needle tract seeding after biopsy of abdominal lesions was miniscule (0–0.009%). Common to these relatively old studies was that they were based on patient and doctor reporting, without performing an active cross-sectional imaging verified tracing of seeding; and therefore the true seeding rate was probably greatly underestimated. Sparsely documented incidences in the more recent studies of the colorectal neoplasm seeding following liver biopsy vary between 10% and 19%. These data consist primarily of relative small case series and reports limited by small sample size. The reported high seeding rates are therefore probably greatly overestimated in these studies. Some authors suggest that invasive diagnostic procedures should be carefully considered due to risk of seeding which can change a potentially respectable localized cancer to an unrespectable one. Neoplasm seeding has been a subject of particular concern for liver surgeons. Tumor seeding is a well-known phenomenon after traditional open surgical procedures as well as after laparoscopic procedures. Tumor seeding has also been reported after ultrasound guided radiofrequency ablative procedures. Experimental studies have shown cancer cell leakage in the needle tract in the majority of biopsy cases. How do we reduce tumor seeding? The co-axial biopsy technique, whereby the biopsy needle is inserted through an introducing needle, is popular with many practitioners who cite improved needle stability and the ability to obtain multiple cores using only one initial puncture as strong advantages of this system. It has been suggested that the co-axial technique reduces the risk of needle tract seeding by isolating the biopsy specimen from the needle tract when the sample is withdrawn. Unfortunately no randomized studies have proved this yet. Furthermore, seeding after using the co-axial biopsy technique has been described. The use of contrast enhanced ultrasound can reduce the need for ultrasound guided liver biopsy in many cases, and this procedure should be reserved to unclear cases approved by the local multidisciplinary team and to cases where oncologic treatment is planned.

Introduction When cytology for pleural fluid is nondiagnostic, thoracoscopy or cutting-needle pleural biopsy or closed percutaneous needle biopsy using Abrams needle (ANPB) can be used to obtain tissue samples. Ultrasound guidance for biopsies performed with an Abrams needle can be used to increase the diagnostic yield of this traditional method. Aim of the study This study aimed to compare the diagnostic validity of ANPB under ultrasound guidance (US-ANPB) with that of medical thoracoscopy in patients with pleural effusion. Methods 30 patients with recurrent exudative pleural effusion of undetermined etiology that have undergone cytologic analysis and could not be diagnosed were included in the study and divided into 2 groups, Group I who underwent medical thoracoscopy for diagnosis (n = 15) and Group II who underwent ultrasound-guided Abrams needle biopsy for diagnosis (n = 15). Comparison between the two groups was drawn in terms of diagnostic sensitivity and complications associated with the methods used. Results The sensitivity and specificity of diagnostic thoracoscopy in group I was 100% & 100% respectively. The sensitivity and specificity of ultrasound-guided Abrams needle in group II was 100% & 100% respectively. No difference was identified between the sensitivities of the two methods. Complications of both groups were of low rate and tolerable. Conclusion If US guidance can be used for biopsies performed with an Abrams needle, the yield of this traditional method can be increased. The use of US-guided Abram’s needle pleural biopsy is simple, safe and well tolerated.

The demand for percutaneous needle biopsy is greater than ever before and with the majority of procedures requiring imaging guidance, radiologists have an increasingly important role in the diagnostic work-up of patients with suspected malignancy. All invasive procedures incur potential risks; therefore, clinicians should be aware of the most frequently encountered complications and have a realistic idea of their likelihood. Tumour seeding, whereby malignant cells are deposited along the tract of a biopsy needle, can have disastrous consequences particularly in patients who are organ transplant candidates or in those who would otherwise expect good long-term survival. Fortunately, tumour seeding is a rare occurrence, yet the issue invariably receives a high profile and is often regarded as a major contraindication to certain biopsy procedures. Although its existence is in no doubt, realistic insight into its likelihood across the spectrum of biopsy procedures and multiple anatomical sites is required to permit accurate patient counselling and risk stratification. This review provides a comprehensive overview of tumour seeding and examines the likelihood of this much feared complication across the range of commonly performed diagnostic biopsy procedures. Conclusions have been derived from an extensive analysis of the published literature, and a number of key recommendations should assist practitioners in their everyday practice.

A computed tomographic-guided percutaneous needle biopsy (CTGNB) is useful as an option for pathologic diagnosis of lung cancer, especially in patients with peripheral small-sized nodules. We aimed to assess the risk of pleural seeding of cancer cells, leading to postoperative relapse with dissemination caused by the procedure.We investigated the clinical outcomes of 447 stage I lung cancer patients. Survival analysis was performed using the Kaplan-Meier method and a log-rank test. Pleural recurrence rates were also determined. Furthermore, propensity score matching analysis was used to reduce background bias from patient characteristics.The 5-year, disease-free survival rate was 89.1% in patients diagnosed with CTGNB, and 85.5% in those diagnosed using a transbronchial biopsy or open lung biopsy procedure. Local recurrence with pleural dissemination was found in 8 of 13 recurrence cases (61.5%) in the CTGNB group, which was higher as compared with the transbronchial biopsy or open lung biopsy group (p0.01). Subset analyses of p stage IB cases and those with subpleural lesions showed that local recurrence with dissemination was significantly more frequent in the CTGNB group (p = 0.02 and p0.01, respectively). In patients with subpleural lesions diagnosed with CTGNB, the rate of local recurrence with dissemination was 15.4%. Propensity score matching analysis confirmed the significantly increased frequency of pleural dissemination after CTGNB.The CTGNB procedure might increase the risk of pleural implantation in stage I lung cancer patients, especially p stage IB cases with subpleural lesions, whereas the overall disease-free survival rate was not affected by this small population of patients with recurrence.

Spondylodiscitis are frequent and clinical challenge for practionners. Axial calcium pyrophosphate dihydrate deposition disease (CPDD) is well known for cervical spine involvement with the crowned dens syndrome but other localisations are probably underdiagnosed in sterile spondylodiscitis. We report a case of recurrent sterile spondylodiscitis with epidural abscess related to CPDD proved by vertebral percutaneous needle biopsy with rapid favourable course under colchicine therapy. Axial CPDD could mimic septic spondylodiscitis with epidural abscess on MRI. Sterile spondylodiscitis are probably underdiagnosed forms of microcrystalline disease. Investigations of the presence of microcrystals should be systematically undertaken with tamponed formalin fixed biopsies. If axial CPDD is suspected, colchicine therapy could be a good therapeutic test and would avoid unnecessary antibiotic treatment.

To evaluate the efficacy of contrast-enhanced ultrasound for the localization of ultrasonically invisible hypervascular lesions in the liver to facilitate percutaneous ultrasound-guided treatment.Forty patients with 47 ultrasonically invisible hypervascular lesions (5-20mm) diagnosed on contrast-enhanced computed tomography were enrolled in the retrospective study. Contrast-enhanced ultrasound (CEUS) with Levovist was performed to localize the lesions both in the early phase and liver-specific phase. Diagnosis of was confirmed by percutaneous needle biopsy where feasible, and on the basis of on treatment outcomes or changes in computed tomography findings in those not amenable to biopsy.Thirty-two lesions were diagnosed as hepatocellular carcinoma (HCC). Contrast-enhanced ultrasound localized hepatocellular carcinoma in 24/32 (75%) lesions, the mean diameter (15.1+/-4.9mm), as measured using computed tomography, being significantly larger than that of the remaining eight lesions (10.5+/-2.1mm). Ultrasound-guided treatment was performed in 19 of the 24 lesions, and transarterial chemoembolization (TACE) was applied for the other five lesions because of difficult percutaneous access. Five of the eight non-visualised lesions were treated by transarterial chemoembolization, and the other three by surgical resection. The beneficial effect of CEUS was significantly greater when the reason for poor initial visualisation was the coarse liver architecture (17/17) than when it was due to adverse location (seven of 15, p0.005). Fifteen of the CT-detected hypervascular lesions were considered to represent false positives for HCC, based on their behaviour during follow-up.Contrast-enhanced ultrasound with Levovist facilitates the application of percutaneous ultrasound-guided treatment by improving localization of ultrasonically invisible hypervascular hepatocellular carcinomas in the liver.

Image-guided percutaneous biopsy is a well-established and safe technique and plays a crucial role in management of cancer patients. Improvements in needle designs, development of new biopsy techniques, and continual advances in image-guidance technology have improved the safety and efficacy of the procedure. Lesions previously considered relatively inaccessible can now be safely biopsied. In this article, we review the various needle types, biopsy techniques, methods of safely assessing difficult-to-reach lesions, the advantages and disadvantages of various imaging modalities, and specific biopsy techniques applicable to different regions of the body.

Lipoblastoma is a rare tumor of embryonal fat occurring predominantly in the first three years of life. This benign tumor has potentials to local invasion and rapid growth. We reported a rare case of mediastinal lipoblastoma. The computed tomography (CT) and ultrasound (US) features, and the roles of percutaneous transthoracic US-guided needle biopsy, are discussed.

Resume But de l'etude Presenter les aspects epidemiologiques de cette affection reputee rare, la demarche diagnostique et les resultats du traitement chirurgical dans une population mediterraneenne. Patients et methodes Les observations des patients operes pour un carcinome hepatocellulaire entre 1987 et 1999, et qui n'avaient pas de cirrhose a l'examen histologique du parenchyme hepatique ont ete retenues. Les donnees ont ete collectees de facon prospective. Resultats L'âge moyen etait de 57,6 ans. II y avait 61 hommes (79 %) et 16 femmes mais un sex ratio de 1:1 pour les 22 patients d'âge Conclusion Le carcinome hepatocellulaire sur foie non cirrhotique n'est pas rare. II est habituellement decouvert a un stade avance, mais reste souvent resecable. La mortalite postoperatoire est faible et les taux de survie sont superieurs a ceux des resections pour carcinome hepatocellulaire sur cirrhose.

Background Magnetic resonance imaging (MRI) has a high soft-tissue specificity which has contributed to its widespread clinical use, developed since the early 1980s. Conventional scanners do not allow access to the patient during scanning; a later generation of scanners has revolutionised patient access, allowing the development of MRI-monitored interventional techniques. Methods We have developed MRI-guided surgical techniques and have tested surgical instruments, composed of a non-ferrous titanium alloy, in an MRI scanner. An adequate set of non-magnetic laparoscopic instruments is available, but these distort the image if left in the scan plane during scan acquisition. MR-compatible endoscopic cameras, a bipolar diathermy machine and anaesthetic equipment are also available. Results Real-time guided-biopsy of intra-abdominal lesions under local anaesthetic has been sucessfully performed using the Flashpoint Tracking system, integral to the Signa SPIO machine. We are investigating a new manganese-containing i.v. contrast medium, which may facilitate image-guided surgery of the liver and pancreas. MR-monitored laser thermoablation of hepatic tumours has also been successful. Discussion We consider that the major role for image-guided laparoscopic surgery will be in the staging and biopsy of intraabdominal malignancy. Open-access MRI has enormous potential, particularly in MR-guided percutaneous needle biopsy, image-guided surgery and thermoablation of tumours. However, further work is needed on the design and development of MR-compatible, conventional and laparoscopic instruments.

During the past three decades, percutaneous renal biopsy has evolved as a valuable method of clinical evaluation of patients with various forms of glomerular proteinuria and primary renal failure. The advent of automated core biopsy needles and ultrasound guidance has substantially improved the safety of needle biopsy techniques and almost eliminated the need for surgical wedge biopsy.

Summary Percutaneous needle biopsies of synovium are successfully used for diagnosis and investigation of joint disease by an increasing number of groups around the world. This procedure can be done in the office with little morbidity; a large number of samples can minimize the potential limitation of sampling error. Clinical indications for ‘imaging the joint' by looking at morphological and other features of the actual tissue include undiagnosed acute or chronic mono- or oligoarthritis, haemarthrosis, suspected deposition diseases, new developments in previous stable disease and less often unexplained polyarthritis. Research into any joint disease can be helped by study of synovium especially using newer immunohistochemical, EM and molecular techniques. This report has reviewed other methods used for obtaining synovium, described the different percutaneous biopsy needles, detailed the methods used for biopsy with the Parker-Pearson needle and described how our group handles tissue so as to obtain maximal impact. The very few side effects of needle biopsy include haemarthrosis and, rarely, needle breakage. Finally, we have provided a brief overview of normal synovium and some aspects of synovium in a variety of joint diseases.

The justification for a renal biopsy is its ability to provide information on diagnostic and prognostic features, and to guide management. These properties are considerably enhanced by close liaison between the reporting pathologist and the attending renal physician. The tissue is obtained almost invariably by percutaneous needle biopsy under ultrasound or CT guidance, and the proper handling of the sample to ensure an accurate diagnosis or a reasonable explanation to correlate with the clinical findings is essential. This handling will be outlined during the presentation, along with recommendations for processing the biopsy and its sectioning. The series of stains used at various levels that are regularly scrutinised for diagnostic assessment will be described. The kidney reacts in a limited number of ways to various types of injuries (e.g., infectious, immunological, toxic, haemodynamic, obstructive and metabolic) to produce a limited range of morphological lesions. Similarly, there are a limited number of clinical syndromes that manifest renal disease to match these morphological findings. Examples of the range of morphological appearances commonly encountered in renal biopsy interpretation will be presented and described, and this range (along with specific disease processes that produce them) will be made available online (courtesy of the RCPA).

Background Embolic tubular epithelial cells in the lumina of glomerular capillary loops have been described following percutaneous biopsy as a rare artifact. Method A 37-year-old male underwent a percutaneous renal biopsy as a part of investigation for proteinuria. Result Epithelial cells with abundant mitochondria and surface villification similar in morphology to proximal tubular epithelial cells were discernible in the glomerular capillary loops on electron microscopy in a percutaneous needle biopsy sample. Conclusion Tubular epithelial cell emboli is a rare artifact of the needle biopsy in which tubular cells or fragments are detached from the tubule by the needle and pushed into the glomeruli through arterioles. Awareness of this artifact is important to avoid misinterpretation as focal proliferative lesion or metastasis.

Small lung nodules undiagnosed by percutaneous needle biopsy have traditionally gone to thoracotomy for diagnosis. We describe a technique using computed tomographic needle/wire lung localization of these nodules, to be resected using video-assisted thoracoscopy. This is less invasive and less painful than thoracotomy and provides for cost-effective definitive diagnosis.

Percutaneous needle biopsy of skeletal muscle was used in 139 patients, to diagnose muscle disease or system vasculitis. 35 specimens confirmed the clinical diagnosis (vasculitis: 7; myositis: 23; miscellaneous muscle disease: 5). No complications have occurred and the material obtained was adequate in 137/139 cases. Needle biopsy is an easy, safe and effective technique, which can be done prior to the standard method of open biopsy in the large majority of cases.

The results of 300 consecutive thoracic needle biopsies have been evaluated. It is concluded that this is a safe procedure for the investigation of peripheral intrathoracic masses. It should not be performed unless excellent facilities for cytopathology are available. Under these conditions there is a high degree of accuracy in differentiating between malignant and non-malignant lesions, particularly if repeated biopsies are performed when the initial results are unrewarding, equivocal or at variance with the radiographic appearances. In this series there was an imperfect correlation between the cytological and subsequent histological cell type except with squamous carcinomas. The indications are changing with the advent of flexible bronchoscopy and the increasing use of chemotherapeutic regimes. Misleading results may be obtained from biopsy of cavitating lesions and necrotic tumours.

Micromethods are described for rapid quantitative lipid analysis of human liver specimens obtained by percutaneous needle biopsy. Total phospholipid, free fatty acids, triacylglycerol and free and esterified cholesterol were separated by thin layer chromatography and, with the aid of an internal standard, quantitated by specific chemical assays. Individual phospholipids were also separated and quantitated. Fatty acid esters were transmethylated and assayed by gas-liquid chromatography. The results of recovery and reproducibility experiments and lipid values for normal human liver are reported. These methods provide a new approach for investigating the pathogenesis of liver disease and may well prove useful in analysing lipids from biopsies of other tissues.

Percutaneous needle biopsy of the vastus lateralis muscle was performed in a patient with a generalised accumulation of neutral triglyceride. Light microscopy revealed a type I fibre predominance, with neutral lipid droplets in both fibre types but larger and with a greater quantity of lipid per unit area in the type I fibre population. Within type I fibres there were at least two populations based on the lipid droplet size and total accumulated lipid per cell. These observations are discussed, and it is concluded that they support the hypothesis of metabolic differences within the type I fibre population with respect to the use of free fatty acids as a fuel source.

A micro radiochemical method has been developed for the assay of the human liver peroxisomal enzyme alanine: glyoxylate aminotransferase (EC 2.6.1.44). The method, based on the electrophoretic separation of [ 14 C]alanine (substrate) from [ 14 C]pyruvate (product) is at least fifty times more sensitive than the currently-used spectrophotometric double enzyme method (Rowsell et al, Int J Biochem 1972;3: 247–257), enabling the enzymatic diagnosis of primary hyperoxaluria type 1 to be carried out on only 100 μg of human liver tissue obtained by percutaneous needle biopsy. The increased sensitivity of the new method allows the assay conditions to be such that they are on the linear parts of the time-course and protein concentration curves. This results in the activities of alanine: glyoxylate aminotransferase in human liver samples being 20–50% higher than those determined by the spectrophotometric method.

Percutaneous needle biopsy of lung lesions has proved useful in the diagnosis of tumors and infectious lesions of the lung. Accurate tissue diagnosis of tumors was obtained in 81 percent of attempts, and an accurate microbiologic diagnosis was obtained in 75 percent of infectious lesions. Eleven percent (23 of 213) of patients biopsied for tumor were spared diagnostic thoracotomy, and only one biopsy gave a false-positive result. There has been no mortality, and the only significant morbidity was a 12 percent incidence of pneumothorax necessitating chest tube insertion. The use of this technique in varied clinical settings has made it a valuable and often primary diagnostic tool for lung lesions.

Bronchoscopic biopsy and percutaneous needle biopsy were retrospectively compared with open biopsy. No procedure resulted in mortality. Nonfatal complications were similar in incidence. Bronchoscopic biopsy approached the accuracy of open biopsy only when applied to infiltrates. Percutaneous needle biopsy approached the accuracy of open biopsy only when applied to nodules. Nonspecific results of either bronchoscopic biopsy or percutaneous needle biopsy were unacceptable as definitive diagnoses.

Glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) activities were measured in percutaneous needle biopsy specimens of human liver tissue and compared with transaminase values in serum obtained on the day of biopsy. Hepatic GPT activity was significantly decreased in liver tissue of patients with alcoholic hepatitis and cirrhosis compared with the activity in individuals with normal livers (P

Previous investigators have documented changes in muscle potassium concentrations in a variety of diseases. Extension of these studies has been limited because of the need for an acceptable procedure for obtaining muscle samples without risk. A percutaneous needle biopsy of quadriceps muscle provides a relatively atraumatic approach to the study of cellular chemistry in children. Evidence is presented that a sample less than 10 −3 the mass of the quadriceps may give significant insight into muscle electrolyte physiology. A preliminary study of muscle potassium in normal children is described which shows that the potassium content of muscle increases with age from 1 to 2,000 days. This represents a significant reduction in the infant's chemical immunity against secondary disorders of potassium depletion during the early postnatal period.

Summary Percutaneous needle-biopsy of skeletal muscle has been successfully used for several years in other countries, but only rarely, if at all, in Great Britain. Complications—haematoma formation or infection—are exceedingly uncommon. The technique is simple and relatively atraumatic and biopsy specimens can be taken in the ward or outpatient clinic for pathological or biochemical studies. Such biopsies will contribute information about muscle as a tissue and on the distribution of electrolytes between the cellular and extracellular spaces of the body. Since samples can be obtained very rapidly, and repeatedly, the technique also makes it possible for muscle energy metabolism to be studied during exercise. The biopsy technique offers a practical means of studying the cellular basis of the symptoms of muscle weakness, excessive fatigue, and effort intolerance.

A technique for percutaneous needle biopsy of the kidney in infants and children,with the use of the amplifying fluoroscope, has been developed. With this technique, success has been obtained in over 97 per cent of the patients upon whom biopsies were performed.

Of a group of 42 children with the clinical diagnosis of acute glomerulonephritis, 3 failed to heal. Histologic features of renal tissue obtained by percutaneous needle biopsy served to differentiate these children from the remainder of the group. The pathologic findings in these three children, characteristic of the changes of chronic glomerulonephritis, suggest that, excluding those who die from early complications, children who appear to have acute glomerulonephritis and fail to recover may have an unusually severe form of acute glomerulonephritis with rapidly progressive glomerular disease or, more likely, either an exacerbation of previously unrecognized renal disease or superimposition of acute glomerulonephritis upon pre-existing renal disease.

Computed tomography (CT) can be used to accurately localize the depth of pulmonary nodules in relation to the chest wall. This examination is helpful before transthoracic percutaneous needle biopsy in those patients whose nodules cannot be localised by conventional methods.

Radiographically and pathologically documented air embolism occurred following percutaneous needle aspiration of the lung. While air embolism is uncommon, it is more likely to occur when the needle is inserted into a rigid portion of the lung as occurs with extensive consolidation, abscess formation, or extensive pleural disease.

I N 1882 WAGNER recognized the association of contraction of the kidneys and hypertension. In 1939 Weiss and Parker’ described the vascular changes associated with pyelonephritis and reported the incidence of coexistent hypertension was 45 per cent. Interest in studying the association of hypertension and pyelonephritis has recently been rekindled by the introduction of percutaneous needle biopsy of the kidney. Renal biopsy studies in hypertensive patients have reported pyelonephritis in 10 to 50 per cent of cases.2-4 An exhaustive study5 of 200 consecutive autopsies in hypertensive Australians revealed 103 patients with histologic evidences of chronic pyelonephritis, 92 with benign nephrosclerosis and 10 with other renal lesions. The histologic diagnosis of chronic pyelonephritis was based on findings of periglomerular fibrosis, colloid casts of the tubules, pelvic mucosal inflammation and interstitial plasma cells. Elsewhere in this symposium, Smythee reports 12 cases of pyelonephritis among 25 patients with hypertension and bacteriuria.